126 
To perform all these functions, the CRIS has been organised in independant 
subsystems. The choice of this configuration has been made for two main 
reasóns : to avoid too important data flow rate links due to image transmis- 
sion between computers and to avoid total stop of the system in case of fai- 
lure of one part. 
There are four subsystems, which undertake the following functions 
CONTREX 
. Interface with SPOT Mission Center, 
. Cloud cover evaluation and catalogue management (interface with SPOT 
IMAGE), 
. Internal management of CRIS. 
TRAITIMAGE 
. Archiving, 
. Preprocessing of level 1, 
. Preprocessing of level 2 (only geometric corrections). 
PRODIMAGE 
. Film generation, 
. CCT checking, 
. OCT copying. 
MES AMERS 
. Ground control point pick up, 
. Registration, 
. Modelisation, 
. Management of the cartographic data bank. 
The hardware configuration of these subsystems are described in the figures 
here after :